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Interface Value

All Superinterfaces:: Mirror

All Known Subinterfaces:: ArrayReference, BooleanValue, ByteValue, CharValue, ClassLoaderReference, ClassObjectReference, DoubleValue, FloatValue, IntegerValue, LongValue, ModuleReference, ObjectReference, PrimitiveValue, ShortValue, StringReference, ThreadGroupReference, ThreadReference, VoidValue

public interface Value extends Mirror

The mirror for a value in the target VM. This interface is the root of a value hierarchy encompassing primitive values and object values.

Some examples of where values may be accessed:

ObjectReference.getValue(Field) - value of a field

StackFrame.getValue(LocalVariable) - value of a variable

VirtualMachine.mirrorOf(double) - created in the target VM by the JDI client

ModificationWatchpointEvent.valueToBe() - returned with an event

The following tables illustrate which subinterfaces of Value are used to mirror values in the target VM --

Subinterfaces of `PrimitiveValue`
Kind of value	For example - expression in target	Is mirrored as an instance of	`Type` of value `Value.type()`
a boolean	`true`	`BooleanValue`	`BooleanType`
a byte	`(byte)4`	`ByteValue`	`ByteType`
a char	`'a'`	`CharValue`	`CharType`
a double	`3.1415926`	`DoubleValue`	`DoubleType`
a float	`2.5f`	`FloatValue`	`FloatType`
an int	`22`	`IntegerValue`	`IntegerType`
a long	`1024L`	`LongValue`	`LongType`
a short	`(short)12`	`ShortValue`	`ShortType`
a void		`VoidValue`	`VoidType`

Subinterfaces of `ObjectReference`
Kind of value	For example - expression in target	Is mirrored as an instance of	`Type` of value `Value.type()`
a class instance	`this`	`ObjectReference`	`ClassType`
an array	`new int[5]`	`ArrayReference`	`ArrayType`
a string	`"hello"`	`StringReference`	`ClassType`
a thread	`Thread.currentThread()`	`ThreadReference`	`ClassType`
a thread group	`Thread.currentThread()` `.getThreadGroup()`	`ThreadGroupReference`	`ClassType`
a `java.lang.Class` instance	`this.getClass()`	`ClassObjectReference`	`ClassType`
a class loader	`this.getClass()` `.getClassLoader()`	`ClassLoaderReference`	`ClassType`

Other values
Kind of value	For example - expression in target	Is mirrored as	`Type` of value
null	`null`	`null`	n/a

Since:: 1.3

Method Summary

Modifier and Type	Method	Description
`Type`	`type()`	Returns the run-time type of this value.

Methods declared in interface com.sun.jdi.Mirror

toString, virtualMachine

Method Details

type

Type type()

Returns the run-time type of this value.

Returns:

a Type which mirrors the value's type in the target VM.

See Also:

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/21/docs/api/jdk.jdi/com/sun/jdi/Value.html